Below are few definitions of biosemiotics as taken from various authors.

“The process of message exchanges, or semiosis, is an indispensable characteristic of all terrestrial life forms. It is this capacity for containing, replicating, and expressing messages, of extracting their signification, that, in fact, distinguishes them more from the nonliving – except for human agents, such as computers or robots, that can be programmed to simulate communication – than any other traits often cited. The study of the twin processes of communication and signification can be regarded as ultimately a branch of the life science, or as belonging in large part to nature, in some part to culture, which is, of course, also a part of nature.” (Sebeok 1991: 22) “The life sciences and the sign sciences thus mutually imply one another.” (Sebeok 1994: 114)

“Biosemiotics proper deals with sign processes in nature in all dimensions, including (1) the emergence of semiosis in nature, which may coincide with or anticipate the emergence of living cells; (2) the natural history of signs; (3) the ‘horizontal’ aspects of semiosis in the ontogeny of organisms, in plant and animal communication, and in inner sign functions in the immune and nervous systems; and (4) the semiotics of cognition and language. Biosemiotics can be seen as a contribution to a general theory of evolution, involving a synthesis of different disciplines. It is a branch of general semiotics, but the existence of signs in its subject matter is not necessarily presupposed, insofar as the origin of semiosis in the universe is one of the riddles to be solved.” (Emmeche 1992: 78)

“In the biosemiotic conception ,the life sphere is permeated by sign processes (semiosis) and signification. Whatever an organism senses also means something to it – e.g., food, escape, sexual reproduction etc., and all organisms are born into a semiosphere, which is to say a world of meaning and communication: sounds, odours, movements, colours, electric fields, waves of any kind, chemical signals, touch etc. The semiosphere poses constraints or boundary conditions upon species populations since these are forced to occupy specific semiotic niches i.e. they will have to master a set of signs of visual, acoustic, olfactory, tactile and chemical origin in order to survive in the semiosphere. And it is entirely possible that these semiotic demands to populations are often a decisive challenge to success. For perhaps more than anything else, organic evolution testifies to the development of ever more sophisticated semiotic means for surviving in the semiosphere…for the most pronounced feature of organic evolution is not the creation of a multiplicity of amazing morphological structures, but the general expansion of ‘semiotic freedom’, that is to say the increase in richness or ‘depth’ of meaning that can be communicated” (Hoffmeyer 1996: 61). “A modern unification of biology has to be based on the fundamentally semiotic nature of life.” (Hoffmeyer 1997)

“From a historical point of view, in the 1960s and 70s Thomas Sebeok, a linguist, launched first the investigation of Zoosemiotics and later Biosemiotics with the goal of studying the biological roots of human semiosis, the path taken by Nature to go from the organic world to the world of signaling, signs, communication and language. In the following years, however, some biologists started pointing out that there are semiotic mechanisms at the very heart of organic life. On the face of this, many biologists would prefer to avoid the issue altogether, which is hardly surprising. But some do not. There are a few of them, today, who believe that the genetic code and the semiotics of life in general are genuine phenomena that can be examined in their semiotic fullness, and who are actually studying the semantic mechanisms of life. They are living in that small academic niche at the outskirts of biology that is known as Biosemiotics, dedicated to building a bridge between biology, philosophy, linguistics and communication studies. Today, its main challenge is to give a deeper scientific understanding not only of biological information but also of biological meaning, in the belief that organic codes and processes of interpretation are basic elements of the living world. Biosemiotics has become in this way the leading edge of the research on the fundamentals of life, and is a young exciting field on the move.” (Barbieri, 2005)